Specific heat studies on Ru substituted FeSi Kondo Insulator

High pressure studies on RuIn3single crystal

“…Further details about the sample assembly and measurements on different systems can be found in [8][9][10]. Specific heat measurements were carried out using quasi-adiabatic heat pulse calorimetry in the range 77-300 K. A heat pulse for a short known duration (∼30 s) was applied to the sample assembly after attaining thermal equilibrium at fixed temperatures and the rise in temperature ( T ) was deduced from analysis of the time-dependent temperature drift curves [11,12]. The heat capacity of the sample holder assembly was measured before mounting the sample and that was subtracted from the total heat capacity in order to extract the specific heat of the sample under study.…”

The thermal expansion of (Fe1−yNiy)Si

“…Many of the physical properties of end-member FeSi have unusual temperature dependencies, including the thermal expansion (Mandrus et al 1994), heat capacity (Mani et al 2008), Seebeck coefficient (Sales et al 1994) and magnetic susceptibility (Sales et al 1994). The unusual properties are caused by its peculiar electron band structure and FeSi is commonly described as either a narrow band-gap semiconductor (Delaire et al 2011) or a Kondo Insulator (Samuely et al 1996, Mani et al 2008. Hybridisation between the silicon 3p and iron 3d bands creates a small gap in the electronic density of states (DOS), which in FeSi (as well as RuSi and OsSi) coincides with the Fermi level (Mattheiss and Hamann 1993, Jarlborg 1997.…”

“…Figure5. Calculated C P for the samples; FeSi-blue, Fe 0.9 Ni 0.1 Sigreen, Fe 0.8 Ni 0.2 Si-red, black symbols are experimental measurements of the heat capacity of FeSi(Krentsis et al 1963, Acker et al 1999, Mani et al 2008. Inset: difference in heat capacities from the Fe 0.8 Ni 0.2 Si phase derived from equation (10), the long-dashed line is C P of the putative metallic-FeSi phase.…”